Abstract
We studied the influence of size and position of assumed slip line and definition of limit state on estimated stability of a slope during an earthquake, performing search of critical slip lines and probabilistic safety assessment. The critical slip line is searched based on 2-dimensional dynamic analysis by Genetic Algorithm, in which not safety factor but limit acceleration is used as the objective function, because the critical slip line depends on the amplitude of input motion. The limit acceleration is defined as minimum peak acceleration of input motion that causes the failure event. The limit sate is defined for both case, balance of slip force and resistance force, and slip displacement. It is indicated in numerical examples that cohesion of residual strength has large influence on position and size of critical slip line, but those of the slip line is not so sensitive to failure probability.
